1. Field of the Invention
This invention relates to drawer interlock assemblies. In one of its aspects, the invention relates to a drawer interlock assembly in which at least two vertically stacked drawers in one or two cabinets are selectively interlocked to prevent more than one drawer from being opened at one time.
2. State of the Prior Art
It is common practice to mount single drawer-bearing cabinets onto walls in an open office plan configuration, for example. Frequently, more than one cabinet is mounted onto a wall in vertical juxtaposition. Typically only one drawer is opened at a time. However, if more than one drawer is open at a time, the wall may experience a substantial amount of stress or could even become unstable.
Drawer interlock assemblies have been used for many years in freestanding cabinets to prevent multiple drawers from being opened at any given time. Most of these interlock mechanisms are fairly complicated and expensive as well as adapted for single cabinet use.
For example, Oehme in U.S. Pat. No. 4,624,511, issued Nov. 25, 1986, discloses a drawer interlock system in which locking flanges on the back of each drawer interface with pivotably mounted latches which are interconnected by a vertically movable rod to lock the drawers in place. A stabilizing rod mounted at the front of the cabinet engages an unlocking mechanism to permit both drawers to be opened at the same time.
The patent to Stringe, 2,597,684, issued May 20, 1952, discloses a drawer lock mechanism in which rearwardly projecting hooks on the back of the drawer engage a vertically mounted locking rod which is pivotable from a locking and unlocking position.
The Key U.S. Pat. No. 159,583, issued Feb. 9, 1875, discloses a system of folding store shelves and drawers wherein an interlock is provided between an upper shelf cabinet and a lower cabinet to lock the lower cabinet drawers in the cabinet when the shelf cabinet is folded down on top of the lower cabinet portion.
The patent to De Fouw et al., No. 4,239,309, issued Dec. 16, 1980, discloses a drawer interlock system in which a vertically mounted interlock bar on each of the cabinet has a plurality of U-shaped lock members which engage front portions of a drawer when another drawer in the cabinet is opened. The lock bar is vertically movable and actuated by opening of the other drawer.
The Janke U.S. Pat. No. 4,394,056, issued July 19, 1983, discloses a drawer interlock mechanism in which one movable locking bar is provided for each drawer and brackets having outer inclined surfaces are used to raise the bar into non-locking position as the drawer is shut. The mechanism requires a number of brackets on each drawer equal to the number of drawers in the cabinet.
The Wood, Jr. et al. U.S. Pat. No. 4,452,498, issued June 5, 1984, discloses a cabinet drawer interlock in which an L-shaped vertical bracket at a back corner of the cabinet interfaces with L-shaped horizontal brackets mounted to each cabinet drawer to prevent more than one drawer from opening at any given time.
The Slusser U.S. Pat. No. 4,355,851, issued Oct. 26, 1982, discloses a drawer interlock system in which a plurality of blocks and wedges is provided in a channel of a predetermined length and the opening of a drawer in the cabinet moves a wedge member into the channel in sliding contact with the blocks and causes the channel to become fully occupied. A second drawer is thereby prevented from opening because the wedge associated therewith cannot be moved into the channel as the drawer is opened.
The Scherrer U.S. Pat. No. 4,077,684, issued Mar. 7, 1978 discloses a drawer interlock for two side-by-side drawers in which two interlockable pivotable members are positioned between two adjacent sliding drawers such that the withdrawal of one drawer causes the associated pivotable member to pivot and interlock with the other pivotable member and thereby secure the other member in a position which blocks the other drawer from opening.
The Mitchell U.S. Pat. No. 3,199,937, issued Aug. 10, 1965, discloses an interlock mechanism for vertically juxtaposed drawers in a file cabinet wherein a spring-loaded control rod interfaces with flanges on the drawers to lock adjacent drawers when one of the drawers has been withdrawn.
The Young U.S. Pat. No. 4,480,883, issued Nov. 6, 1984, discloses a drawer interlock mechanism for vertically stacked drawers in a cabinet in which a U-shaped channel mounted within the cabinet mounts locking bars and cam elements, the latter of which interact with pins extending from the side walls of each drawer in the vertical stack. As a drawer is withdrawn, the pin interacts with a corresponding cam element in the channel, causing it to pivot and thereby raise the locking bar to a position contacting both the top and bottom caps of the U-shaped channel. In this way, other drawers are prevented from opening when the one drawer is withdrawn.